Recognition of random shapes in brain-damaged patients.

In two experiments the hypothesis was tested that left hemisphere-damaged patients and especially those with aphasia are impaired in the recognition of meaningless random shapes because they fail to attribute a meaning to the shapes. In a multiple choice recognition task, left hemisphere-damaged patients with aphasia and left and right hemisphere-damaged patients without aphasia were shown complex random shapes together with either a pictorial cue (experiment I and II) or a dotted drawing of its outline on which more or less outstanding parts were specially marked (experiment I). In experiment I no difference between conditions or groups emerged. In experiment II aphasics and left hemisphere-damaged patients without aphasia were generally inferior to right hemisphere-damaged controls and performed significantly better when a pictorial cue was given than when it was absent, however only when the conditions were given in a certain order.